This invention relates generally to cylinder heads in internal combustion engines. More particularly, this invention relates to cylinder heads having carriers for a rocker arm assembly in a diesel engine.
Internal combustion engines have intake and exhaust valves for air to enter and exhaust to leave each cylinder. The valves connect to rocker arms, which rotate on a pivot ball to open and close the valves. Typically, there is a separate rocker arm for each valve. Push rods operate the rocker arms and extend through the engine cylinder head to connect to a camshaft, via tappets. As the camshaft rotates, the push rods actuate the rocker arms to open and close the valves. The camshaft is designed to open and close the valves in conjunction with the cycling of the piston in the cylinder.
In the prior art, a pedestal is required as an upper support for the pivot ball on the rocker arm. The pedestal is bolted to the cylinder head to complete the assembly. This design requires significant bosses in the head and a substantial pedestal to support the valve train loads. The bosses and pedestals add weight to the engine. In addition, the rocker arms and related components are assembled along with the rest of the engine. This increases the assembly time of the engine.
Accordingly, there is a need for a rocker carrier with sufficient structural support to reduce engine weight and a modular design to reduce assembly time of the engine.
The present invention provides a rocker carrier with a modular design that adapted for use with a cylinder head in an internal combustion engine. The rocker carrier comprises a body portion having a continuous peripheral wall including a front and rear wall connected between a first and second end wall, a plurality of rocker arm pedestals integrally formed on the body portion and disposed between the rear and front walls, a top surface able to cooperatively engage a valve cover, and a bottom surface able to cooperatively engage a cylinder head. The rocker arm pedestals of the rocker carrier are further made up of dual rocker arm pedestals and/or an end rocker pedestals.
The rocker carrier of the present invention can also comprise a plurality of support fins, a high pressure oil line passage integrally formed adjacent to the rear wall, a plurality of high pressure oil reservoir bosses integrally formed on the body portion and disposed between the rocker arm pedestals and the front wall, a plurality of exterior head bolt passages, a plurality of carrier bolt bosses, a plurality of glow plug passages, a plurality of electrical connector passages, and an oil drain passage, and a plurality of valve cover bolt bosses formed adjacent to the rear wall.
The rocker carrier is preferably connected to the cylinder head. A valve cover secures to the top of the rocker carrier thus enclosing the cylinder head. One of the functions of the rocker carrier is to mount the rocker arm assemblies containing the rocker arms and related parts. The rocker arm carrier also mounts a high pressure oil rail that provides high pressure oil to thereby actuate fuel injectors. In addition, it provides a place to pass electrical wires from the engine harness to the fuel injector and glow plug under the valve cover.
The rocker carrier of the present invention reduces the bosses, pedestals, and other structural support components used for a rocker arm assembly which results in weight savings. In addition to the weight savings, the modular design permits pre-assembly of the rocker carrier thereby reducing the assembly time of the engine in the assembly plant. The rocker carrier also has funnel shaped guides in a bottom or underside surface of the rocker carrier for aligning the push rods. The rocker carrier will also allow for increased bolt stretch to produce an acceptable cylinder head to crank shaft joint.
The following drawings and description set forth additional advantages and benefits of the invention. More advantages and benefits are obvious from the description and may be learned by practice of the invention.